Background on Metal Ion Chemistry

Modified from Turner et al. (1981) Stumm and Morgan (1981) Millero and Hawke (1992). 

Some natural sources containing these functional groups are phytochelatins (siderophores), biopolymers (e.g., proteins), and humic substances (see chapters 8 and 9 for more details on these compounds). Compounds such as phytochelatins are used by algae (Donat and Bruland, 1995) and higher plants (Grill et al., 1985) to enhance metal uptake capability in the natural environment, particularly in systems where their concentrations are exceptionally low. 

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